1. Field of the Invention
The subject automatic burner driven generator system is generally directed to a system for generating and maintaining sufficient electric power to drive a load. More specifically, the subject automatic burner driven generator system is one which operates in such highly automated and efficient manner that it provides reliable and safe electric power generation over an extended period of continuous service.
Moreover, the subject automatic burner driven generator system is adapted to provide such high levels of performance in substantially low power applications wherein, for example, output power levels even below 5 watts are required.
In numerous applications, there is a need for low levels of primary electric power at locations where established grid power is not readily available. An example of such an application is that of a remotely-located gas pipeline monitoring station. Typically, such monitoring stations are unmanned and located in remote regions without access to grid electric power; however, they do have a source of gaseous fuel (such as natural gas or propane) readily available. There is a need in these and other applications for a fueled power generator system which operates with sufficient reliability and automation to effectively permit one-switch operation following installation.
There is a need, moreover, for such a power generator system not only having low cost, but which exhibits low internal power consumption. There is a need for such power generator systems having microprocessor-based controls, integrated rechargeable battery charging, and sufficient communication capability.
2. Description of the Related Art
Power generation systems for supplying low levels of primary power at remote locations are known. Such power generation systems employing various types of technology are also known, but are generally deficient in a number of respects. For example, systems simply employing primary batteries are quite costly to maintain, and are prohibitively so in many cases. Systems employing solar power devices are neither cost effective nor reliable enough to be practicable within a broad range of geographic locations. The controllers in systems employing such power devices are not readily adaptable to other methods of energy conversion.
Power generation systems employing thermoelectric devices are also known. Such known systems, however, fail to offer the level of reliability to enable extended periods of unattended low power generation and sufficient battery charging. In many applications, such thermoelectric power generation systems are often prohibitively expensive and invariably operable to provide a satisfactory degree of reliability only at output power levels higher than would otherwise be desirable. Furthermore, such known thermoelectric power generation systems fail to offer efficient management of ancillary power needs and lack an integrated control system that, if necessary, actuates multiple re-ignitions of an incorporated burner device; supports simple and convenient diagnostic activities thereon; and, insures safe operation.
Other shortcomings of known thermoelectric power generation systems include their requisite need for specialized installation and drawn out initial startup procedures. They are not, therefore, adapted for xe2x80x98one-switchxe2x80x99 operation, as is the subject automatic burner driven generator system.
Specific prior art references known to the Applicant include U.S. Pat. Nos. 5,599,181; 4,131,413; 5,495,829; 5,335,730; 3,627,588; 3,881,962; 4,773,847; 5,422,826; 5,450,869; 5,604,758; 5,705,770; 5,753,383; 5,917,144; and, 6,019,098; as well as a Product Manual entitled Telan/DACAP Engineering and Applications Manual distributed by Teledyne Brown Engineering, March 1996. The systems disclosed in such prior art references, however, fail to disclose the combination of features incorporated in the subject automatic burner driven generator system for powering an external load.
For instance, U.S. Pat. No. 5,599,181 issued to Aoki, et al. is directed to a combustion apparatus having a built-in storage battery. The apparatus fails to incorporate control measures as comprehensive as that of the present invention, nor is the apparatus designed to power external loads. One example in this regard is that the apparatus fails to incorporate battery charging measures that are carried out in adaptive manner to optimize efficiency.
The TELAN commercial generator described in the non-Patent literature document does not incorporate control measures as programmable and highly automated as a microprocessor-based measures. Hence, it does not facilitate one-switch operation. Nor does it provide such features as automatic delayed re-light and built-in diagnostic operation.
U.S. Pat. No. 4,131,413 issued to Ryno is directed to a self-contained electric igniter wherein the ignition pilot is actuated by a rechargeable battery to generate a spark. The Patent, however, fails to disclose a microprocessor-based control system, much less such a control system that incorporates a comprehensive, highly automated set of control functions.
U.S. Pat. No. 5,495,829 is directed to a natural gas-powered, forced or induced draft water heater apparatus. The apparatus includes a thermoelectric module and a through-chamber heat sink. It incorporates a microprocessor controller for regulating the natural gas supply line and an electric blower that operates at approximately 4.0 volts. Nevertheless, the Patent fails to provide among its integrated control functions such things as communication capabilities, diagnostic capabilities, or acceptance testing features.
U.S. Pat. No. 5,335,730 issued to Cotham is directed to microprocessor-based activation of various valves to control the flow of liquids from a well head. The disclosed control measures, however, fail to incorporate the comprehensive combination of integrated control functions necessary to enable the degree of highly automated operation effected in accordance with the present invention. Furthermore, the control measures disclosed utilize as the preferred power source a solar array coupled to batteries. It is unclear, moreover, as to whether or not the disclosed control measures are operable at sufficiently low internal power consumption levels to realize low device costs.
There is, therefore, a need for a burner driven generator system operable in highly-automated yet efficient and economic manner. There is a need for such a generator system employing a comprehensive set of control measures sufficient to enable one-switch activation by a user and continual operation thereafter for powering a load over extended periods of time. There is a need for a generator system so operable even at low power levels.
It is a primary object of the present invention to provide a burner driven generator system for powering a load in highly automated yet efficient and reliable manner, even in low power applications.
These and other objects are attained in the automatic burner driven generator system of the present invention. The subject automatic burner driven generator system for powering a load generally comprises: a burner unit for generating thermal energy; a thermoelectric converter unit operatively coupled to the burner unit for transducing at least a portion of the thermal energy to a first electric power signal; a rechargeable battery unit operable to generate an output power signal for powering the load; a charging unit operably coupled to the thermoelectric converter and rechargeable battery units; and, a controller for automatically controlling the actuation of the units in programmed manner. The charging unit is operable to adaptively convert the first electric power signal to a second electric power signal for charging the rechargeable battery. The controller includes a microprocessor unit programmably configured to selectively actuate the units in accordance with a plurality of predetermined operational states.
In one preferred embodiment, the predetermined operational states include: initial, startup, warmup, run, wait, shut down, and test states. Also in one preferred embodiment, the battery unit includes an enabling portion which, in turn, includes a solenoid valve for selectively admitting the entry of a fuel from a fuel source into the burner unit and an igniter for igniting the admitted fuel. The solenoid valve in that embodiment is switchable between open and closed configurations; and, the rechargeable battery unit is operatively coupled to the burner unit for electrically powering the enabling portion. The solenoid valve is operably powered for transitioning between its open and closed configurations in the embodiment by at least a portion of the output power signal, whereafter the solenoid valve is operably powered for maintaining the open configuration thereof by an ancillary power signal.
Also in one preferred embodiment, the charging unit is operable responsive to the controller to generate the second electric power signal in temperature compensated manner relative to an ambient temperature parameter. The controller in one preferred embodiment includes a current limiter coupled to the charging unit for maintaining the first electric power signal at a current level no greater than a predetermined maximum current value.